As for the operational speed of the computer is increasing, the power consumption is also increasing accordingly. Also, because the operational speed of computer components is faster and faster, the required power consumption is increased. The power supply is the power source for computer. Because sometimes the output power from the power supply could not afford the total requirement of the power consumption components in the computer, it will cause the system instability, and even cause the damages to the power supply. Thus, there are many information related manufacturers emphasizing the energy efficiency of the power supply, and there presented many devices and methods for measuring computer performance.
The conventional measurement device for computer performance employs the method for cascading an external resistor at one end of computer for the input of the power supply, and by measuring the current and voltage for the resistor to convert into the input power of the power supply. On the opposite, the end at the motherboard or other computer components, such as CPU and memory, would be cascaded with an external resistor additionally, and, similarly, by measuring the current and voltage for the resistor to convert into the output power. However, either the power supply or the computer components being cascaded with an external resistor, it would have changed the original circuit structure of the computer device, and the additional external resistor would cause the voltage drop at both ends of the resistor, and generate the excess energy consumption. Therefore, the measured computer performance would have lower precision, and limited reference value.
There is another kind of conventional measurement device for computer performance, which emphasized for measuring the total output power of the power supply, and the measured resistance for the resistor would be far less than the impedance of the computer motherboard. However, the method is required to add one more power adapter card between the power supply and the motherboard; and, connecting the power supply to the power adapter card, and connecting the power adapter card to the motherboard to supply the power for the computer operation; and, the resistor for power measurement is located on the power adapter card. The disadvantage for this method is that it is required to add a power adapter card, which caused the increased cost.